Antigenic composition obtained by V8 proteolysis of a protein from S. mansoni

Abstract

An antigenic composition against S. mansoni comprising an 8 kD peptidic fragment associated with a suitable vehicle, the 8 kD peptidic fragment being obtained by controlled proteolysis using V8 protease of a 28 kD protein obtained from S. mansoni is described.

We claim: 
     
       1. An antigenic composition for a mammal against S. mansoni, which comprises a peptidic fragment of 8 kD associated with a suitable vehicle, said 8kD fragment reacting with a cytotoxic antibody W2AD12 (deposited at the CNCM as No. I-553) and being obtained by controlled proteolysis of a 28kD protein isolated from S. mansoni, the controlled proteolysis comprising: a) subjecting the 28kD protein of S. mansoni to proteolysis by V8 protease in Tris-HCl buffer containing SDS to produce an 8kD fragment,   b) stopping the proteolysis reaction by adding thereto a mixture of 2-mercaptoethanol in SDS, and boiling at 100° C. for a time sufficient to stop proteolysis, and   c) collecting said 8kD peptide.   
     
     
       2. The antigenic composition of claim 1, wherein the said enzymatic digestion of said 28kD protein by said V8 protease is effected for about 30 minutes at 30° C. 
     
     
       3. The antigenic composition of claim 1, wherein said mixture used to stop said proteolysis reaction comprises 2-mercaptoethanol in a proportion of 1 μl for 3 μl of 10% SDS. 
     
     
       4. The antigenic composition of claim 1, wherein said Tris-HCl buffer in which said 28kD protein is dissolved is a buffer of 100 mM to 125 mM and contains 0.08 to 0.12% of SDS.